The disclosure of Japanese Patent Application No. 11-370634, filed on Dec. 27, 1999, including the specification, drawings and abstract, is incorporated herein by reference in its entirety.
1. Field of Invention
The invention relates to an attachment structure of a spring unit in a structural component formed by attaching the spring unit to a frame body.
2. Description of Related Art
A structural component formed by attaching a spring unit to a frame body has been applied to various fields, for example, seat frames such as a frame constituting a seat cushion serving as a seating portion of a vehicle seat and an ordinary chair, and a frame forming a seat back serving as a backrest. The spring unit constituting such a structural component has a rectangular shape that is formed by a plurality of wire springs connected with each other at each intersection. The spring unit is attached to the frame body by hooking the upper and lower right and left ends of the spring unit to the corresponding frame portions of the frame body, and hooking the intermediate portion of at least one of four sides of the spring unit to a corresponding frame portion of the frame body.
Generally, the spring unit forming the structural component is attached to the frame body by caulking each hooked portion of the spring unit to the corresponding frame portion of the frame body. However, caulking is a rather troublesome operation in the case where the spring unit has many hooked portions. Moreover, in the case where the frame body is molded from an alloy as a molding material, the caulking cannot be used due to the property of the molding material.
For example, in recent years, the vehicle seats have been reduced in weight, in part by integrally molding a seat frame serving as a frame body from an alloy as the molding material, for example, a magnesium alloy and an aluminum alloy. In the case where the seat frame is used as a frame body, the caulking cannot be used due to the property of the molding material.
It is an object of the invention to enable a spring unit to be easily attached to a frame body upon forming a structural component without using the caulking to attach the spring unit to the frame body.
In order to achieve the above-stated object, an structural component of one exemplary embodiment of the invention includes a frame body having a plurality of frame portions and a spring unit composed of a plurality of wire springs connected to each other at each intersection. Each end of the spring unit is hooked to a corresponding frame portion and an intermediate portion of at least one side of the spring unit is hooked to at least one frame portion. The structural component also includes a projecting hooked portion unit provided on the side frame where the intermediate portion of at least one of four sides of the spring unit is hooked. The hooked portion is inserted into a intersection hole of the side frame and hooked at a portion on a rear surface of the side frame.
According to the structural component described above, the intermediate portion of the spring unit can be attached to the frame body by attaching a hooked portion in the intermediate portion of the spring unit to a corresponding frame portion of the frame body. This eliminates the need to use the caulking to attach the spring unit to the frame body. Accordingly, even if the caulking cannot be used due to the molding material of the frame body, the spring unit can be easily attached to the frame body. Even if the caulking can be used, the troublesome attachment operation can be eliminated, thus improving operation efficiency.